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  #1  
Old 04-13-2012, 05:23 PM
Alycidon Alycidon is offline
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Default 17 Hornet rim thickness.

Does anyone true the rims of these cases ?. Measure new cases rim thickness with a mic and you get some disturbing variations, I have had considerable side to side variations on the same case.

My 17AH shoots about MOA using Remmy brass straight out of the box and annealed before and after forming which is fine for a short range vermin rifle, but a bit of fine tuning could halve that.

Has anyone lathe turned the rims on the neck side to a consistent thickness
, if so what accuracy results did you get compared to non turned cases?.

A
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Old 04-13-2012, 05:55 PM
moorepower moorepower is offline
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I sm considering reaming another "chamber" in some steel and filing off the high spots to uniform after firing on the ammo, and before firing on the fired and unfired brass. It would only be .001-.0025 so I don't think it would weaken the brass. I don't know if it would help, but I don't see that it would hurt.
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Old 04-13-2012, 07:34 PM
iiranger iiranger is offline
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Default Rws???

Years ago in a magazine and of course I forget which one, a hornet fan claimed that he got much improved accuracy by using RWS cases BECAUSE the rims were uniform, very uniform. Nothing good to say about uniformity of US brass rims. Makes sense. Called "headspace" in the rimmed case. Mike Bellm had that series of wildcats on the .308 family of brass and would cut a relief in the chamber so shooter could use .307 case if wished... but HARPED on consistent headspace on shoulder, either way. Luck. Happy trails.
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Old 04-13-2012, 07:52 PM
rick w. rick w. is offline
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There was a time when I spent hours with the Wilson trimmer, trying to machine the heads of PPC cases flat. Not sure if it made a lot of difference, but benchrest is a bit of a mental game.

I thought about trying the same thing with hornet and bee brass, uniformity and all of that stuff. I finally, slowly, came to conclusion to quit trying to make my chambers meet the brass dimensions. Rims do vary it seems. So I have gone to the shouldered methods for holding the case in the chamber, and the rim cut becomes a don't care at least for me.
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  #5  
Old 04-13-2012, 08:46 PM
Alycidon Alycidon is offline
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[quote=iiranger;136908]Years ago in a magazine and of course I forget which one, a hornet fan claimed that he got much improved accuracy by using RWS cases BECAUSE the rims were uniform, very uniform. Nothing good to say about uniformity of US brass rims.


I have recently become aware of this and am talking to a riflesmith who does this case machining work and has prooved it works. He was doing this work is the 1960s, started on his own BSA 22 Hornet. At the time RWS brass was not readily available and he used Winchester brass. I am wondering if this is a proven technique or one that has perhaps been lost in the mists of time and perhaps now needs re airing. They say nothing much is new in shooting.

In the UK RWS brass is three times the price of Remmy, around one pound a case, so about $1.30

A
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  #6  
Old 04-13-2012, 08:46 PM
montdoug montdoug is offline
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Fire-form the cases then neck size only till the cases get sticky, (if indeed they do?). I have one batch of 50 .17 Ackley Hornet cases that haven't needed the shoulders bumped yet with 8 firings. After forming if you neck size only the rim thickness (within reason of course) is immaterial IMO.
Last week we had a thread on "headspace" and I mic'd 10 case rim's out of one MTM box of 50 .17 AH cases. Even in that small sampling they varied by .005 but the same batch of cases that have been neck sized only is shooting bugholes.
I'd consider turning rims a huge waste of time but then I weight segregate cases and a lotta other stuff that others think is a waste of time.
If you decide to do it be sure to shoot before and after groups to see how much actual effect the process has and post your results for us .
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  #7  
Old 04-13-2012, 08:50 PM
Alycidon Alycidon is offline
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[quote=rick w.;136909]There was a time when I spent hours with the Wilson trimmer, trying to machine the heads of PPC cases flat. Not sure if it made a lot of difference, but benchrest is a bit of a mental game.

I watched an international BR shot loading between relays, he just dropped his charges into the cases, he won the comp.

One thing I do know is that the first twenty five rounds out of a new barrel are the most accurate. Have often shot tiny tiny groups when fireforming.

A
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Old 04-13-2012, 08:57 PM
rick w. rick w. is offline
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I suspect that the pressure of the real match/competition was not there during fire forming..............same with me too.
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  #9  
Old 04-13-2012, 11:50 PM
Lopili Lopili is offline
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Quote:
Originally Posted by iiranger View Post
Years ago in a magazine and of course I forget which one, a hornet fan claimed that he got much improved accuracy by using RWS cases BECAUSE the rims were uniform, very uniform.
Same kind of story appeared in Australia, however the gains were due to thicker rims being a better match to the Brno Zkw465s which are notorious for 'headspace problems'. That problem often goes away with European brass with thicker rims ... or loading judiciously to account for it ... or a K-Hornet rechamber. There are a few cartridges were the metric to imperial conversion gets a bit hazy leading you to believe you have gun problems when its in fact brass incompatability problems. 6.5x55 comes to mind as a classic for this where US brass is often undersized in the rim and through the solid case head.
Cheers...
Con
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  #10  
Old 04-14-2012, 12:14 AM
johno johno is offline
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Exactly, good to see your reading some history young fella
The RWS brass has a rim thickness of about 1 thou more than US brass, if memory serves me correctly. This combined with small pistol primers was the answer to accuracy & head space problems with ZKW 465.

But because I will never do another build I have no further interest in the subject

Johno
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